disconnect size

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if you are on the 08 Code and the disconnect does not require ocp, you are compliant. the language in 440 that reflects that of 430.110 is not in the 05 or earlier.
 
I don't have my code book handy, but I thought the 115% was taken from the rated full load amps that you get from the tables, and that is based on motor HP. Is that not right?
 
buck33k said:
Could a 30 amp fused disconnect be used?
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Why would you use a 30 am disco. and why fused. I would use a 60 amp pullout and a 40 amp breaker at the panel to avoid future nuisance tripping.

Our fuseless 60 amp discos cost about $10.00. They don't even sell a 30 amp unit-- not sure they make one.

If the unit says max. fuse then you must use a fuse but if it says max hacr then you don't need a fuse.
 
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Dennis Alwon said:
Why would you use a 30 am disco. and why fused. I would use a 60 amp pullout and a 40 amp breaker at the panel to avoid future nuisance tripping.

Our fuseless 60 amp discos cost about $10.00. They don't even sell a 30 amp unit-- not sure they make one.

If the unit says max. fuse then you must use a fuse but if it says max hacr then you don't need a fuse.
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Dennis,
I know what your saying and I agree. The fuse type 30 amp disconnect was provided for this installation (split AC unit in warehouse). I want to make sure it meets minimum requirements.
I'm OK with the branch circuit and breaker size and the 115%, but now I'm unsure about fusing this disconnect at 40 per the AC nameplate. I do'nt know if this is permitted or even possible? It could be the 30 amp disconnect is out based on this consideration. Additional input might clear this up.
 
buck33k said:
AC nameplate: Minimum circuit ampacity 25 amps, Max fuse 40 amps, max breaker 40 amp.

Circuit is #8 with 40 amp breaker.

115% of minimum circuit ampacity is = 28.75 amps.

Could a 30 amp fused disconnect be used?
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12 AWG feed, 60A fusible pullout disco w/ 40A fuses, and a 40A breaker & your good to go... 8AWG even better,but 12 AWG is the bare min. size for a A/C with a min. ampacity of 25A.
 
norcal said:
12 AWG feed, 60A fusible pullout disco w/ 40A fuses, and a 40A breaker & your good to go... 8AWG even better,but 12 AWG is the bare min. size for a A/C with a min. ampacity of 25A.
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I'd say that, if you're okay with the #12 (and not NM, right?), you should be okay with a 30a disco.
 
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